Question

To what maximum concentration gradient could E. coli accumulate beta-galactosides if its pumping of H+ ions from inside the cell to outside the cell resulted in a ΔpH of 1.5 (interior higher by 1.5 unit) and a membrane potential of –124 mV (interior negative). In other words, imagine that the E. coli are going to use the free energy of the H+ ions coming back into the cell (which they are poised to do) to bring in (or cotransport) beta-galactosides into the cell against their concentration gradient such that the maximum possible gradient allowable is obtained, which is due to the maximum amount of free energy available to do so. Again, the temperature is 37 °C, and F = 23.1 kcal/V mol. Report your answer to the nearest ones.